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Topic: 1974 450sl drowning in fuel Reply to Thread
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  Topic Review (Newest First)
06-27-2019 06:34 AM
cushjbc Neil,

Reference post #29 . . .

"Is this TS2???" - yes sir that is the one.

A more glaring issue in that photo is the absence of your AAV and the entire idle control mechanism. That stuff needs to go back on. I am unable to assist until it does - not that I am unwilling it's just out of my ability to understand how the engine is supposed to function without the OE parts on it. Maybe others here or on other forums understand mods like this but I don't have the expertise for it.

The wiring in your engine bay has had some modifications. Part of the information I want to give you covers this topic. Your ECU cannot do its job if the signals from those sensors are not clean. Survey your engine harness and tell me what you think about it. I have some experience successfully repairing that stuff and can help you do it. Again, I only know how to work on unmodified Bosch D-Jetronic systems.

It is obvious you are reading . . . I recommend focusing on the material specific to your 1974 Mercedes-Benz 450SL. Brad Anders and Joe Kerfoot are Porsche 914 enthusiasts. They are talented engineers with lots of loosely pertinent information on D-Jet fundamentals. That is graduate level info that is nice when your car is running - TMI when your car is not running.
06-27-2019 06:06 AM
Neil W. Lareau
Quote:
Originally Posted by cushjbc View Post
Neil,

The picture in post #21 is not a TS2 sensor. It appears to be a temp sensor for your temp gauge which is aft and inboard of cylinder number 4 (right side aft cylinder head = hottest part of the cooling circuit). Take a brass wire brush and clean it off. I'm willing to bet it will have VDO part numbers on it. If that part was pulled from the front of your engine where the TS2 sensor is, we need to get you a new correct part. I have several spares willing to loan before you go throwing money at it. This way we can diagnose to narrow down the problem which may or may not be limited to TS2.

The TS2 sensor is Bosch part 0 280 130 014. It is a negative transfer coefficient (NTC) thermistor. It looks like this:

So I have it backwards? The water temp gauge temp sender is the one in the back (cylinder 4)?? I do have a twin blade temp sensor in the front next to the thermotime switch. TS2 is in the FRONT of the engine?
06-27-2019 05:51 AM
cushjbc Please take pictures of the two sensors on the coolant port at the front of your engine. I'm interested in seeing the coolant temp sensor (TS2) and condition of the wiring on it, the thermo-time switch and its wiring, and the start valve area and wiring where you said you did some removal and replacement work.

PM me - I want to send you some data for your car that is way to big to post here. We can also exchange emails and start sending parts for diagnosis.

There is nothing visibly out of order in the picture of your fuel regulation package shown in post #26. The hose clamps with screw to toothed band are not recommended on fuel injection systems because they do not provide a uniform seal - I have gobs of the correct type if you can't find them. That Goodyear hose may not be the correct 7.5mm ID for our fuel system. I buy Contitech hose from AutohausAZ - sold by the meter. That rubber hose has to be in perfect working order. Leaks have been known to cause engine fires in D-Jet systems.
06-27-2019 05:38 AM
cushjbc
Quote:
Is this the wrong part?
Neil,

The picture in post #21 is not a TS2 sensor. It appears to be a temp sensor for your temp gauge which is aft and inboard of cylinder number 4 (right side aft cylinder head = hottest part of the cooling circuit). Take a brass wire brush and clean it off. I'm willing to bet it will have VDO part numbers on it. If that part was pulled from the front of your engine where the TS2 sensor is, we need to get you a new correct part. I have several spares willing to loan before you go throwing money at it. This way we can diagnose to narrow down the problem which may or may not be limited to TS2.

The TS2 sensor is Bosch part 0 280 130 014. It is a negative transfer coefficient (NTC) thermistor. It looks like this:
06-27-2019 04:23 AM
Neil W. Lareau
Quote:
Originally Posted by cushjbc View Post
Standing by for pictures - can you also take some of the fuel pressure regulator and damper at the rear of the engine?
I'll get a pic of the fuel pump / damper shortly. I do have a new fuel pump, but this problem existed with OEM pump also.
06-27-2019 04:13 AM
Neil W. Lareau
Quote:
Originally Posted by Troglodyte View Post
My guess is that is the wrong one. VW & porsh are the only ones that would measure head temp.

This is a Gem of Info.

http://w107.pbworks.com/f/DJetronic.pdf
Thanks. I've also fallen in love with https://members.rennlist.com/pbanders/ecu.htm
06-27-2019 04:12 AM
Neil W. Lareau
Quote:
Originally Posted by lsmoz View Post
It is the wrong one, there should be another next to it with a two blades for the connector to go to, you will definitely have one.
And based on the temp/ohm chart from the post above it would appear to be an air temp sensor stuck where a cylinder head temp sensor should go. That still doesn't explain why I'm running rich, but it is an error to eliminate. Thanks.

For reference, though, this is the cylinder head temp sensor. It is located on the cylinder head near #4 cylinder just before the firewall. It is near the vacuum manifold banjo connection that goes to the brake booster and the transmission modulator.
06-26-2019 11:40 PM
lsmoz It is the wrong one, there should be another next to it with a two blades for the connector to go to, you will definitely have one.
06-26-2019 04:12 PM
Troglodyte My guess is that is the wrong one. VW & porsh are the only ones that would measure head temp.

This is a Gem of Info.

http://w107.pbworks.com/f/DJetronic.pdf
06-26-2019 08:13 AM
Neil W. Lareau Cylinder head temp sensor (TS2) from my 450sl is 600ohms room temperature and drops as I heat it. According to the Anders D-Jet site, it should be 2k cold (60F) and drop to 50 ohms hot (250+ F).
Open circuit would make the ECU command full rich, ground would command lean.

Is this the wrong part? Looking at new components, they don't specify resistance values.
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